Originally Posted by sonicgroove
Alright so I finally recruited some help and got these subs moved from the pallet to their new home. Setup is rough and placement is still debatable. Priority is testing to ensure everything is operating within specifications. I also manually tuned the subs to roughly gauge performance and potential. I don’t have any equipment to measure sound performance so everything I do is by ear and customized to my preference. The pair of captivator 4000ULPs replaced a Mirage Omni S12 and a Klipsch KSW-12 (I know, it’s like going from a Honda Civic to a Lamborghini Huracan). I proceeded to connect the power cables that arrived with the subs to different power outlets along with my mono cables to the left/LPE input. Flicked the power switch on and set the amp to auto. It clicked and the green indicated light lit up. Unfortunately, a loud hum followed. This was also true for the other sub. I pulled the mono cable out and the hum went away, it was dead silent. This verifies the source is not the subwoofer itself and rather another ground loop problem. I didn’t have this issue with the previous subwoofers but as some said higher performance subwoofers tend to be more sensitive to ground induced noise. I tried different outlets and it wasn’t until I put them all on the same power source that the hum nearly ceased. It’s still present but the difference in audible hum from a gain of 1-2 clicks on the sub amp is now equivalent to the hum produced at a gain of 17-18 clicks which is a significant reduction. Now that the hum is more tolerable I began to test the subs by playing audio files and clips from movies. To my surprise I got zero output from the subs. I tried increasing the volume but no change. I figured the signal output from the receiver was not enough for the subs to detect. My previous channel level setting for the subs was -12db (lowest setting possible). I dialed down the gain on the subs to 4 clicks and changed sub channel level to 6db hoping it would result in a change. The changes worked and I am now getting bass out of the subs. I balanced it out to -3db sub channel level and a gain of 17 clicks (max is 20 clicks). I also set delay on the 4k captivator coffee table to about 3 clicks as that seem to have the greatest impact on bass. I tested a few more songs and videos and at this point I was astonished to hear tones I never heard before. By no means did the system sound good due to lack of tuning but it was apparent that these subs were producing frequencies the previous setup could not. Not only were they producing those frequencies but the spl was intense. It was so ridiculous I constantly experienced that uncomfortable floating stomach sensation; that deep earth-rumbling - floor shaking fear that arises from the calamity of an earthquake, aka the fear of impending doom. I started looking at the amp settings and noticed the LF adjust knob was turned all the way up. I wasn’t entirely sure of its function (still not so sure) but testing revealed that decreasing it decreased low frequency spl (does this act like a high frequency attenuation but instead boosts bass per drop in octave? If so does anyone have specifics on it?). My previous subs did not have this ability so I adjusted the receiver’s EQ settings to increase sub channel level incrementally at lower frequencies, couple that with the LF adjust settings set to max on both 4ks then you can get an idea of why I felt like I was going to die each time a low frequency blasted out of the subs in the test audio/video clips. At this point I have them set to cut and it’s much better. Ultimately I’d like to learn exactly how the sub amp's LF adjust setting works so I can use it to fine tune the system to my preference when all is said and done with MCCAC. The auto-on feature was also tested and appears to be working. At this point I just need to get rid of the hum and somehow increase the signal output to the subwoofers. I ordered a pair of blue jean subwoofer isolation transformers and a pair of female rca to dual male rca Y-adapters in hopes that they will resolve my issues.
That is my cousin sitting on the sub to give you a better perspective of size. He was the one who assisted in the transport of these monsters. BTW, shoulder dolley + movers dolley FTW. To move them without would be incomprehensible.
Congratulations on the new setup.
The feet that are attached, did put those on or did they come that way?
FAMILY ROOM - Totem Tribe II LCR, JL Audio E-112, Anthem MRX 720, Apple TV, WD HDTV, Panasonic 55" Plasma
BASEMENT THEATRE - Paradigm Studio 100 v5, 690 v5, 10x4 v5, Anthem AVM 60, Outlaw Audio 7700 & 7125, 2x JTR Captivator S2s, X-Box One, Apple TV, HTPC, Ben-Q W1070, 106" screen